1. Field of the Invention
Apparatus and methods consistent with the present invention relate to magnetic recording mediums and fabricating the same, and more particularly, to magnetic recording mediums having a burst pattern, suitable for a medium in which a position for magnetic recording is patterned with a magnetic material in a fabrication stage, such as a discrete track medium or a patterned medium.
2. Description of the Related Art
As the amount of information processed substantially increases, demands for information storage devices enabling recording/reproducing of data at higher densities are growing. Specifically, hard disk drives using a magnetic recording medium are desirable as an information storage device for a computer and various digital devices, since they have large capacities and high-speed access characteristics. In the case of a magnetic recording medium having a continuous magnetic recording layer (hereinafter, referred to as a continuous medium), when the size of a bit, which is the smallest unit of data, or the pitch width of a data track are reduced to a predetermined size, more noise occurs due to influence of adjacent areas and recording stability is substantially decreased. Thus, there is a limit in increasing a recording density by increasing a linear recording density (BPI) which is a density in a direction in which a disk rotates, or a track density (TPI) which is a density in a radius direction of the disk.
As such, research into a medium in which a position for magnetic recording is patterned with a magnetic material in its fabrication stage, such as a discrete track medium or a patterned medium is being performed. A discrete track medium has a magnetic recording layer which is patterned with a plurality annulus shaped data tracks in its fabrication stage. A patterned medium has a magnetic recording layer which is patterned with a plurality of island-like shaped bit dots in its fabrication stage. At this time, a separation area between the data tracks or bit dots can be empty or filled with a nonmagnetic material. In the case of a discrete track medium or a patterned medium, a position for magnetic recording is isolated magnetically, and thus, the density of data tracks can be increased and data can be recorded at a high density.
Meanwhile, in a magnetic recording medium, servo information required to position a magnetic head at a desired location on the magnetic recording medium should be recorded before a user's data is written. In the case of the discrete track medium or the patterned medium, a servo pattern containing the servo information can be formed together with a data track or bit dot which is patterned in a process of fabricating the magnetic recording medium. This method is known as a pre-embedded servo method.
However, the related art pre-embedded servo method has a problem that it is difficult to accurately adjust a magnetization direction in respective servo patterns. As for the perpendicular magnetic recording, a magnetic signal is determined according to a magnetization direction in a medium, that is, whether the magnetization direction is an upward direction or a downward direction. When a servo pattern is formed together with a data track or bit dot, it is difficult to accurately adjust the magnetization direction of the servo pattern in an upward direction or a downward direction. For example, when a servo pattern is formed and then an Alternating Current (AC) erase is performed, many domains having up/down magnetization directions can exist in respective servo patterns, and thus signals from respective servo patterns are too small and a degree of precision of a servo can be decreased. When a servo pattern is formed and then a Direct Current (DC) erase is performed, magnetization directions of all the bits are the same and thus the signal acts as a DC signal, which is not desirable to for processing the signal. In addition, when magnetization directions of all the bits are the same, bits may be thermally unstable.